Vol. 6 January 2015 Asian Journal of BiodiversityAsian Journal Vol. 6 ofJanuary Biodiversity 2015 CHED Accredited Research Journal, Category A-1 This Journal is in the Science Master Journal List of Print ISSN 2094-5019 • Electronic ISSN 2244-0461 Thomson Reuters (ISI) Zoological Record doi: http://dx.doi.org/10.7828/ajob.v6i1.695 Diversity and Abundance of Shallow-water Sea Cucumbers in Samar and Leyte, Philippines MARGARITA T. DE LA CRUZ ORCID No. 0000-0003-2243-1699 [email protected] JEROME BENEDICT P. CABANSAG ORCID No.0000-0002-4049-3861 [email protected] MA. BRENDA P. GAJELAN-SAMSON ORCID No. 0000-0002-0737-7121 [email protected] FRANCEL A. DIAZ ORCID No. 0000-0002-1110-330X [email protected] ROSE JANE P. DIODOCO ORCID No.0000-0003-3111-5313 [email protected] University of the Philippines Visayas Tacloban College, Tacloban City ABSTRACT Combined inventory of commercially collected sea cucumbers in buying stations and fishery-independent surveys of fishing grounds and marine protected areas (MPA) in Samar and Leyte conducted from January – December 2012 revealed 60 species of shallow-water holothurids distributed under Orders 49 Asian Journal of Biodiversity Vol. 6 January 2015 Apodida, Aspidochirotida, Dendrochirotida and Molpadiida. Three of the 15 unidentified species,Paracaudina spp. and Holothuria sp. are possible new species report in the Philippines.Species’ diversity of Samar and Leyte is high but the density of each species is very low ranging from 0.03 – 60.64 ind/ha with all commercially exploited species having densities <1 ind/ha.Catch per unit of effort (CPUE) calculated from results of timed gathering in fished areas of Guiuan, Eastern Samar and Maasin City is likewise low at 4.2 ind/gatherer/ hr and 5.8 ind/gatherer/hr respectively. The CPUE in Palompon, Leyte is high at 235.6 ind/gatherer/hr but Holothuria albiventer, a species of no commercial value in the global market composes 87.5% of the catch. The MPAs also show relatively high CPUE values at 50 ind/gatherer/hrand 90 ind/gatherer/hr for Bagonbanua Marine Reserve and Fish Sanctuary in Guiuan, Eastern Samar and Tabuk Marine Park Fish and Bird Sanctuary in Palompon, Leyte respectively albeit also composed of low commercial value species. Keywords - holothurids, species diversity, abundance, Leyte-Samar Philippines, new species record INTRODUCTION Sea cucumbers are among the most adapted and diverse marine invertebrates found in almost all types of marine habitats and in varying depth. Estimates of the number of sea cucumber species worldwide varies. Pawson (1982) and Smiley (1994) gave a total of 1,460 species belonging to 6 orders, 25 families and 199 genera. Conand (2004) and Toral-Granda (2006) placed the number of sea cucumber species at 1,500 with new species still being described each year. Sea cucumbers are traded mostly as dried beche-de-mer or trepang (99%) and to a lesser extent as frozen or salted (Kalaeb et al. 2008; Kinch et al. 2008a). There is a developing market for ornamental/aquarium specimens, live, chilled or soaked in brine. Dried sea cucumbers, however, make up 99% of those globally traded (Choo 2008a; Brown et al. 2010). In addition, new uses of dried sea cucumbers are also being developed such as in pharmaceuticals and cosmetics (Kerr 2000; Bruckner 2006; Choo 2008a). The increasing demand for trepang, mostly by foreign markets has caused over exploitation of the resource. What used to be unexploited low value species are now also targeted. The number of commercially exploited species worldwide rose from 50 (Brown et al. 2010) to 66 (Purcell 2010; Purcell et al. 2011). Bruckner (2006) and Conand (2004) listed 50 Asian Journal of Biodiversity Vol. 6 January 2015 and categorized 43 main commercial species exploited globally as high, medium, and low commercial values. In Asia, 52 of the reported 125 species (Choo 2008a) are commercially exploited. The Philippines is among the top exporters of dried sea cucumbers second to Indonesia (Conand 2004; Akamine 2005; Toral-Granda 2006). The number of species traded rose from fivewhen the trade begun in the 1990s to the current 33 species (Trinidad-Roa 1987; Schoppe 2000; Akamine 2002; Choo 2008b). Dried sea cucumbers are exported to China Hong Kong Special Administrative Region (SAR), Singapore, Republic of Korea, Taiwan province of China, and Japan (Gamboa et al. 2004; Choo 2008b). Clearly, sea cucumbers provide livelihoods to municipal fishers, local processors and traders (Conand 2004; Gamboa et al. 2004; Kinch 2008a). Maintaining the diversity and population of sea cucumber species is not just necessary to sustain livelihoods. It likewise sustains ecosystem services (Coleman and Williams 2002; Conand 2004; Toral- Granda 2006; Wolkenhauer et al. 2010). OBJECTIVES OF THE STUDY This study thus aimed to determine the species composition and abundance of shallow-water holothurids in the Samar-Leyte area. Clark and Rowe (1971) identified 97 species of shallow-water sea cucumbers in the Philippines. Similar studies conducted in specific parts of the country (Reyes-Leonardo 1984; Schoppe 2000b; Kerr et al. 2006; Olavides et al. 2010) brought the pooled number of identified species to 125. Eastern Visayas has a long standing trepang fishery but only Schoppe (2000b) has documented the holothurids of Cuatro Islas, Inopacan, Leyte. MATERIALS AND METHODS Inventory Seven municipalities and cities in Samar and Leyte with known sea cucumber fishery indicated by the presence of dried sea cucumber traders were selected for the species inventory. These are San Antonio in Northern Samar, Catbalogan City in Samar, Guiuan and Lawaan in Eastern Samar, Palompon and Leyte in Leyte, and Maasin City in Southern Leyte (Figure 1). Available sea cucumbers from traders (also known as buyers), and wet markets in each area were identified and photographed. Specimens/samples of unfamiliar species were bought for 51 Asian Journal of Biodiversity Vol. 6 January 2015 tissue extraction, preserved in 95% ethyl alcohol and brought to the laboratory for ossicles analysis. Since the available species in the buying stations are the commercially important species only, local gatherers were contracted to collect up to three individuals of whatever species of sea cucumbers (i.e. edible or not and/or with or without commercial value) they can find in their fishing ground. Whenever three individuals of a species were available, one is preserved in 95% ethyl alcohol as whole specimen. The other two specimens were relaxed in 10% MgCl2 sea- watersolution before these were measured and weighed. Tissue samples for ossicle examination were then taken from the dorsal and ventral section and the tentacles placed in vials with 95% ethanol and brought to the laboratory for ossicles examination. In some cases animals were dissected for internal anatomy examinations. Cursory field surveys were also conducted in Eastern Samar (Guiuan, Salcedo, and Lawaan), Samar (Zumarraga), Leyte (Palompon), and Southern Leyte (Macrohon and Maasin City). Specimens were identified using published field identification guides and other references (Clark and Rowe 1971; Rowe and Doty 1977; Reyes-Leonardo 1984; Conand 1998; Schoppe 2000b; Kerr et al. 2006; Samyn et al. 2006; Samyn et al. 2010; O’Loughlin 2011; Purcell et al. 2012). For less common species, photographs of the specimens and the ossicles were sent to the Invertebrate Laboratory of Dr. Marie Antonette Junio-Meñez at The Marine Science Institute, University of the Philippines, who verified/facilitated identification. Figure 1. Municipalities and cities where rapid species inventory of shallow- water sea cucumbers was conducted 52 Asian Journal of Biodiversity Vol. 6 January 2015 Abundance Fishers were hired to gather shallow-water holothurids in selected areas of Samar and Leyte. The sites selected were Bagonbanua Marine Reserve and Fish Sanctuary (Bagonbanua) and five fishing sites in Guiuan, Eastern Samar (Fig. 2); six fishing sites in Maasin City (Fig. 3); Tabuk Marine Park Fish and Bird Sanctuary (Tabuk) and five fishing sites in Palompon, Leyte (Fig. 4). The type of habitat/substratum on each fishing ground was noted. Gathering was done during low tide in the evening or after midnight as practiced by the sea cucumber gatherers. The length of time spent gathering and the estimated area covered were recorded. In some cases, the fishers were instructed to gather for one hour only. The catch of each fisher was sorted, identified, photographed, counted and measured (length, body width and weight). Animals that were not needed for ossicles analysis were returned to the MPAs. Figure 2. Sites of fishery-independent survey – Guiuan, Eastern Samar 53 Asian Journal of Biodiversity Vol. 6 January 2015 Figure 3. Sites of fishery-independent survey – Maasin City, Southern Leyte 54 Asian Journal of Biodiversity Vol. 6 January 2015 Figure 4. Sites of fishery-independent survey – Palompon, Leyte 55 Asian Journal of Biodiversity Vol. 6 January 2015 Data Analysis The sea cucumber density (number of individuals per hectare), species population density (number of individuals per species per hectare) and catch per unit of effort (number of individuals per gatherer per hour) were calculated from the data obtained. Species diversity was determined using the Shannon Index of General Diversity (H). A comparison of the species composition between sites was also determined by computing the Index of Similarity (S). RESULTS AND DISCUSSION Species Composition The sites surveyed for sea cucumbers are sandy-rocky areas (mostly with dead corals and coral rubbles) interspersed with seagrasses except for Leyte, Leyte and Southern Leyte where a muddy bottom was also surveyed in each site. Samar and Leyte has at least 60 species of shallow-water sea cucumbers belonging to Orders Apodida, Aspidochirotida, Dendrochirotida and Molpadiida (Table 1). This includes those identified from the buying stations. Of these, 45 were identified to the species level and 15 still need further examination for proper identification (Appendix 1). The unidentified species are specimens collected from the field surveys.